1. Field of the Invention
The present invention relates to a method for controlling a call in a communication system.
2. Discussion of the Related Art
In CDMA (Code Division Multiple Access) call processing methods, there are generally two methods for transmitting a dialed number to a system (or BTS =base transceiver subsystem) when a user makes a call. Specifically, there are an en-bloc or functional address signaling method, and an overlap or stimulus address signaling method.
In the enbloc address signaling, a station is provided with a processor for processing a portion of call processing function for itself without help from a communication network. This signaling method is used in ISDN""s or mobile communication networks of recently developed communication service networks. Using this method, the station stores information regarding a number dialed by a user applied and transmits the stored information at a time when the user presses a xe2x80x9csendxe2x80x9d button. In other words, the en-bloc address signaling is a signaling method in which the address digits are assembled into one block for onward transmission, the block containing all of the address information necessary to route the call to its destination.
In the overlap address signaling, a call is processed under the control of a switchboard without any processing function of its own. In this signaling, when the user lifts a receiver, the switchboard senses this and transmits a dial tone. Then, when the user dials, the switchboard senses every dialed number and controls the call. That is, the overlap address signaling is a signaling method in which the onward transmission of address of address signals from a mobile switching center may commence before the reception of all the address signals over the preceding link has been completed. This method is similar to that of a PSTN. En-bloc address signaling is more efficient to transmit the address signal, but in this signaling a calling user is required to input the xe2x80x9csendxe2x80x9d button as above mentioned.
The call control between a mobile station and a BTS in a CDMA mobile communication system is conducted according to an en-bloc address signaling defined in standards of EIA/TIA IS-95 and ANSI J-STD-008. FIG. 1 illustrates a WLL-CDMA mobile communication system.
Referring to FIG. 1, a WLL (Wireless Local Loop) system is provided with FSUs (Fixed Subscriber Units) 10, BTSs 11, and a WLL BSC (Base Station Controller) 12. A CDMA system is provided with FSUs 10, mobile stations, BTSs 11, a base station manager 14, a CDMA BSC 15, a mobile switching center (MSC) 16, and an HLR (Home Location Register) 17. The FSU 10 corresponds to the mobile station of a radio station, and the STS 11 is a radio interface connecting the mobile station and the BSC 12. The BSC 12 controls the BTSs 11, processes vocoding of a voice packet, and conducts an interfacing function in which the mobile station subscriber is connected to a PSTN. Particularly, the BSC 12 or 15 accommodates a plurality of BTSs 11. A radio communication is made between the BTS 11 and the mobile station 13 until a time when a radio traffic channel is set up. However, once the radio traffic channel is set up, radio communication is made between the mobile station 13 and the BSC 12 or 15. In order to explain a signal processing procedure to/from the mobile station 13, in general, the BSCs 12 and 15 and the BTS is called as a base station (BS), collectively. The BSCs 12 and 15 are connected to a BSM (Base Station Manager) 14 for system management and maintenance. And, as shown in FIG. 1, the CDMA system is further provided with a MSC 16 for number interpretation and switching and an HLR 17 for location management of the mobile stations 13.
FIG. 2 illustrates a standard procedure for processing a call between a mobile station (MS) and a base station (BS) defined in a CDMA system standard. The standard procedure for processing a call between the MS and the BS is as follows. When a mobile station 13 transmits a mobile origination message containing all numerals dialed by a user toward the BS through an AC (Access Channel), which is a reverse channel (201), the BS transmits a BS acknowledge order for the mobile origination message toward the MS through a PC (Paging Channel), which is an forward channel (202). That is, the mobile origination message is a signal for requesting an initiation of a call, and the BS acknowledge message is a message informing an orderly reception of the mobile origination message.
Then, radio sources required for processing the call are assigned between the BTS and the BSC in the BS. Then, a null traffic signal is transmitted from the BTS toward the MS through the traffic channel which is an assigned forward channel (203), for informing an availability of the assigned traffic channel. A channel assignment message containing all assignment information is provided from the BTS in the BS toward the MS through the paging channel (204). The channel assignment message contains a CDMA channel of the assigned 1.25 MHz band frequency, a code channel of radio traffic channel, and frame offset information to match a synchronization for load spreading, and etc. Then, a traffic channel (TC) link is set up between the BTS and the BSC in the BS. Then, the MS provides a traffic channel preamble signal, a preliminary signal, to the BTS in the BS through the traffic channel to the BTS assigned according to the channel assignment message (205). As explained, since there is the TC link set up between the BTS and BSC, the BSC provides a BS acknowledge order to the MS through a forward traffic channel in response to the TC preamble (206), and the terminal, i.e., the MS, acknowledging the forward traffic channel, provides an MS acknowledge order which permits to acknowledge an reverse traffic channel to the BSC (206).
After recognition of such data, the BTS and BSC transmit a responsive signal (207). Thus, both a forward traffic channel and a reverse traffic channel are set up between the MS and the BSC. Then, the BSC in the base station provides a service connect message, informing a requested service is available, to the MS (208), and, in response to the service connect message, the MS provides a service connect complete message which acknowledges the service connect message to the BSC (209). In this instance, the MSC provides a ring back tone to the MS through the BSC (210). As has been explained, a traffic channel is set up through a procedure of confirming service options between the MS and the BS, and the MS receives a ring back tone over the traffic channel.
As shown in FIG. 1, the FSU 10 in a related art WLL-CDMA communication system is provided with a xe2x80x9csendxe2x80x9d button for processing a call in en-bloc address signaling method identical to a general CDMA communication system. When a user lifts a transceiver and dials, the FSU 10 stores the number dialed by the user, and starts to provide the stored number to abase station at a time when the xe2x80x9csendxe2x80x9d button is pressed by the user. On reception of the number, the BS controls the call in interface with the BSCs 12 and 15 and the MSC 16 using the aforementioned standard procedure between the MS and the BS. A related art WLL communication system is a PSTN in which a wireline telephone system is replaced. Therefore, users in the related art WLL system use terminals in the same way as the terminals used in the wireline telephone system. However, in a WLL-CDMA system, the en-bloc address signaling is used in processing a call between the related art FSU and the system. Therefore, a call set up is started when the user presses a xe2x80x9csendxe2x80x9d button after the user in the WLL-CDMA communication system finishes dialing of all the numerals or after a preset time period elapses.
The WLL system is a communication system employed by users who need to make a fast communication between people working in a limited area like airport guards. Therefore, the en-bloc address signaling method employed in the WLL-CDMA system is not convenient in that the user must wait for the call set up. It is expected that the CDMA 2000 system will be used for the WLL system operation, and therefore should support the wireline service and wireline equipment access through appropriate terminations. The wireline equipment is called the aforementioned FSU. However, the related art WLL-CDMA communication system is not convenient in that the xe2x80x9csendxe2x80x9d button must be pressed as the WLL-CDMA communication system employs the en-bloc address signaling method.
Accordingly, the present invention is directed to a method for controlling a call in a communication system that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a method for controlling a call in a communication system, in which the call can be made without pressing a xe2x80x9csendxe2x80x9d button in a call between a terminal and a base station.
Another object of the present invention is to provide a method for controlling a call in a communication system, in which the existing overlap address signaling can be employed in a radio communication system.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the communication terminal monitors on/off state of a hook switch. If the hook switch is at off; the terminal generates a dial tone within itself; and monitors generation of information on a number dialed by a user. Upon generation of the first information on the dialed number, the terminal stops generation of the dial tone. And, the terminal conducts a previous operation as well as sets up a radio traffic channel with a base station based on a preset protocol. The information of the dialed number is stored in a memory in the terminal during conducting the foregoing process. Upon setting up of the channel, the terminal builds up the stored information into a form of message, and transmits to the base station. As the present invention employs the overlap address signaling, overlapped sending of the messages are possible. That is, after the radio traffic channel set up, the information of a number dialed by the user is built up in the same form of message after sending the information already stored, and transmitted to the base station in preset units. Since the present invention applies the overlap address signaling to the CDMA communication system and the WLL-CDMA communication system, a xe2x80x9csendxe2x80x9d button is required no more, which is required in the case of en-bloc address signaling application. The same effect as a wireline communication system can be obtained out of a radio mobile communication system, and a call setting time can be shortened because the terminal is not required to recognize the last digit, and, furthermore, and the present invention is favorable in application to a WLL-CDMA communication system which requires a wireline communication system.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.